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Wednesday, 29 June 2016

Today marks HMS Terror’s
two-hundred and third birthday - the
anniversary of her launch in Topsham, Devon on June 29th, 1813. Within a year
of her launch, Terror would be harassing
American cities along the Eastern Seaboard, and would even have an epic poem
written about her exploits by Francis Scott Key. Today, when Americans sing
their national anthem, they reference the history of our favorite exploration
vessel.

This date also marks the third anniversary of the start of
the Building HMS Terror blog, and
today we’ll be celebrating our respective anniversaries by discussing Terror’s pumps.

By 1845, Terror had
at least five pumping mechanisms installed, though it likely had other moveable
“fire pumps” as well. For her size, Terror
had a relatively large number of water management devices. Comparing the 1836 upper
deck and profile plans of Terror to
the 1839 plans shows that an additional two common pumps were
installed just behind the forehatch, while the main pumps flanking the main
mast were upgraded and replaced.

These changes were likely a response to the near sinking of Terror during George Back’s arctic
expedition of 1836-1837. In the spring of 1837, ice damage to Terror’s sternpost and keel created leaks
so severe that five feet of water gushed into her hold every hour. Back ordered
his men to work the pumps continuously during Terror’s return voyage across the Atlantic. The crew became so exhausted
that they had to beach the vessel at the closest landfall, at Loch Swilly in
Ireland.

Rice, the shipwright responsible for Terror’s 1839 refit, responded to this near disaster by upgrading
all of Terror’s pumping systems. He
also introduced penstocks into the limber board system in the hold, which
allowed the crew to manage the flow of bilge water into her well.

Below, I’ll discuss each of Terror’s new pump systems in turn.

Massey’s (Massies)
Patent Pumps (Bilge):

Massey’s patent pumps were a reliable flywheel pump system
of a type that became very popular on civilian and navy vessels in the latter
half of the 19th century. Testing of Massey’s pumps began in 1833 and timed trials
on board HMS Thunderer showed clear
advantages over traditional chain pumps. Water discharge rates over short durations
were similar to the chain pumps, but at greater periods of time, the Massey pumps
outpaced the chain pumps significantly (1). The main advantage of the flywheel
design seems to be that “it [did] equal work with less fatigue to the men” (1).
The trial was so impressive to the Admiralty that they installed Massey’s pumps
on HMS Vestal in 1834 (2), and
increasingly on Royal Navy vessels thereafter.

Massey’s pumps were a double action “lift and force” pump,
consisting of a camshaft driven by two crank handles. The camshaft drove two 18
inch piston rods that powered the pumps. A heavy iron flywheel was mounted on
the fore end of the camshaft, and, once in motion, it assisted in maintaining
the momentum of rotation (thereby making the crank handles easier to turn). Unlike
chain pumps, Massey’s pumps were very difficult to clog, and could “…discharge a block of wood 9
or 10 inches in diameter”(1). This was obviously
the perfect pump for an arctic expedition vessel.

My plans for the Massey pumps on board Terror are derived from measurements shown on the 1839 plans of Terror and Erebus, with additional information gleaned from the somewhat more
detailed HMS Investigator plans.
Cross sectional details, especially of the fly wheels and piston rods, were
derived from historical images of similar flywheel pumps, as I was unable to
locate the patent for Massey’s 1833 pump design.

Plans for Massey's Patent Pumps, as installed on HMS Terror in 1839.

Common Pumps (Bilge):

Terror was fitted
with two common, or suction pumps, also known as "elm tree pumps" due to the
use of a single bored-out elm trunk as their barrel or tube. Elm was used because of its general resistance
to water, though other water-resistant woods could be employed. The pumps were
extremely simple, consisting of a brake (or handle), a spear (or piston) and two
valves, and were thus very easy to make and repair. The advantage of placing two
common pumps in the fore of the ship was that the fore hold could be pumped out
independently of the rest of the ship; which could be critical in a situation
such as Back found himself during the 1837 Atlantic crossing.

Plans for HMS Terror's common pumps, as installed on HMS Terror in 1839.

Truscott’s Pump
(Fresh Water):

Truscott’s pump was a simple invention that revolutionized
the way water was stored and retrieved on Royal Navy vessels. Inspired by a
visit to an ale house in 1812 (3), Truscott designed a relatively simple iron
pump attached to a small diameter pipe system that led to the hold. Just like in
the ale houses, he attached a flexible leather hose to the end of the pipe and
fed it into the water casks. This obviated the need to move the
casks to retrieve water. This was a major boon on sailing vessels, because moving
casks to retrieve water was time consuming, dangerous, and inevitably impacted
the ship’s trim, requiring periodic rearrangement of the ship’s casks and
ballast. This simple invention eventually led to the use of permanent iron
water tanks on sailing vessels, which ultimately resulted in the abandonment of
shingle and iron ballast.

A plan of Truscott’s pump (ZAZ6848), dated 18th September
1814, is held by the National Maritime Museum. The 1839 lower deck plan for Terror and Erebus indicates that one Truscott pump was located at the rear
of the ship’s stove, on the starboard side, close to the door to the sickbay. This pump permitted the crew and the ship’s cook
to access fresh water as it was need. Since the water tanks in Terror’s hold surrounded the Sylvester stove/furnace,
it is possible that the device could have be used throughout the winter months.
However, it is likely that the fresh
water tank above the Fraser stove provided enough for the ship’s needs without
using the hold tanks (at least during the winter months when fresh water ice
was available).

Truscott's pump (in red) as installed on HMS Terror in 1839.
The ship's water tanks and Fraser's stove appear in blue.

References:

1. The Nautical Magazine: A Journal of Papers on Subjects
Connected with Maritime Affairs in General. 1833. Page 292.

2. Sharp, James. 1858. Memoirs of the Life and Services of
Rear-Admiral Sir William Symonds, Surveyor of the Navy from 1832 to 1847. Longman
Brown Green Longmans & Roberts, London. Page 153.